The set of Inappropriate Boners is an amorphous subset of the Universe of Boners. Inclusion in this subset depends on who has the boner, as well as when, where, and why they have it.
According to Wikipedia, "an erection is physiological phenomenon where the penis becomes enlarged and firm. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated sexual arousal."
According to everyone who has a penis, an erection (a.k.a. 'a boner') is when your dick gets hard whenever, wherever, if, and only if, it jolly well feels like it.
Boners are important for boning (see how the etymology works?) because a boner is usually required for penetration and ejaculation. Unfortunately, the correlation between boners and boning is rarely as neat as we would like it to be.
Sometimes, men don't get boners in situations in which they should. This is called 'erectile dysfunction' and is a topic for another page.
Our present discourse concerns men getting boners in situations in which they should not. These boners are called 'inappropriate.'
A. Boners from Inappropriate Sexual Arousal
These boners, like appropriate boners, are the result of sexual arousal. The problem here is that the sexual arousal comes from something by which it is bad to be aroused.
These boners are unique in that they are the only type of boner that might cause your friends, family, fellow citizens, or government to try to stop you from going certain places.
Depending on what exactly caused your arousal, these places might include:
B. Boners from things that are Awesome
Sometimes, the human male will get a boner just because something is awesome. It is important to mention these boners, because they are so often misunderstood by females (and even some males). The key thing to stress here is that these boners are in no way an indicator of sexual arousal, but rather an indicator of awesomeness.
To make the point even clearer: if you get a boner watching Batman beat the crap out of people, this does not necessarily mean that you are into dudes or violent role-playing. If you get a boner from seeing Bruce Wayne with his shirt off, you are probably into dudes. If you maintain an erection for the duration of Batman Begins, you are into dudes, have good taste in movies, and are awesome.
No-apparent-reason-boners (N.A.R.B.s for short) are the most perplexing of all inappropriate boners, since they happen for no apparent reason. They occur most frequently in adolescence and then taper off as one's junk slowly stops working well with age. N.A.R.B.s wouldn't be much of a problem if they happened in the privacy of one's own home, but they rarely do.
The most common places to get a N.A.R.B. include:
Morningwood is an important type of N.A.R.B. Most men wake up with a boner, regardless of what they were thinking about before they went to sleep. The appropriateness of morningwood depends largely on context.
Times when morningwood is appropriate:
Times when morningwood is inappropriate:
Times when morningwood is extremely unfortunate:
D. Debatable Boners
Just like that Hitler joke you made at a Jewish retirement community, sometimes the appropriateness of boners is subjective. For example, many a man has found himself, at one point or another, in the "friend zone." This is a situation in which a man is attracted to a woman, but she thinks of him as "just a friend."
Suppose you are in this situation. Now suppose the friend in question gives you a hug, and you in turn get a noticeable erection. She might be inclined to call this an inappropriate boner, whereas you might be inclined to think that she's a cold-hearted cocktease and resent her for how warm her breath feels against your neck and how soft her breasts feel against your body.
Cracked has already talked at length about inappropriate boners in the Bible, so we won't get into it in depth here. We'll just point out that, one time, Lot got drunk enough to not realize he was boning his daughters, but somehow not so drunk that he couldn't maintain an erection. It should be noted that this inappropriate boner allegedly allowed for the continuation of the Jewish lineage through history and thus served God's will.
In Plato's Symposium, there is a young man named Alcibiades, who totally wants to bone Socrates. He shows up to a party drunk and complains for several pages about his repeated failure to do so. Here's a snippet.
"My next idea was to invite him to the gymnasium with me. We took exercise together, and I was sure that this would lead to something. He took exercise and wrestled with me many times when no one else was present. What can I tell you? I got nowhere" (Symposium 217c).
So yeah, basically his plan was just to go to the gym and hope that this would happen